Early-age pore-structure evolution in internally cured concrete with super-absorbent polymers: A multiscale study

作者：Zhiyi Wei, Xinyuan Zhang, Li Ma, Yinbo Zhang, Rui He · 发表于：Construction and Building Materials · 年份：2025 · DOI：10.1016/j.conbuildmat.2025.144932 · 被引用次数：15 · 研究领域：Concrete Properties and Behavior、Concrete and Cement Materials Research、Microbial Applications in Construction Materials

Superabsorbent polymers (SAPs) have been widely applied as internal curing agents to mitigate autogenous shrinkage and enhance hydration, yet their influence on the pore structure of concrete remains insufficiently understood. In particular, the regulation of early-age pore development has received limited attention, despite its decisive role in determining long-term durability, transport properties, and volumetric stability. To address this gap, this study employed a comprehensive multiscale experimental approach to investigate the pore structure evolution of SAP-modified concrete. Specifically, hardened air void analysis, mercury intrusion porosimetry (MIP), and nitrogen adsorption–desorption (BET) methods was performed to characterize the pore structure from the macroscopic to the microscopic scale. In addition, X-ray computed tomography (X-CT) was employed to visualize the three-dimensional pore morphology and quantify the evolution of pore number and spatial distribution. Results showed that pore refinement and stability (characterized by a reduced fraction of pores >100 μm and minimal variation of pore size distribution between 1 d∼7 d) were jointly governed by water-to-cement ratio, SAP dosage, and particle size. The mixture showing the most balanced pore-structure evolution was achieved at the w/c ratio of 0.40, the SAP dosage of 0.20 %, and the particle size of 60–90 mesh. BET and MIP analyses revealed that the peak water-release effect occurred between 1 d and 3 d, ...